Diabetes mellitus is a chronic metabolic disorder caused by an inability of a person's pancreas to produce sufficient amounts of the hormone, insulin, such that the person's metabolism is unable to provide for the proper absorption of sugar and starch. This failure leads to hyperglycemia, i.e., the presence of an excessive amount of glucose within the blood plasma. Persistent hyperglycemia has been associated with a variety of serious symptoms and life threatening long-term complications such as dehydration, ketoacidosis, diabetic coma, cardiovascular diseases, chronic renal failure, retinal damage and nerve damages with the risk of amputation of extremities. Because healing is not yet possible, a permanent therapy is necessary that provides constant glycemic control in order to constantly maintain the level of blood glucose within normal limits. Such glycemic control is achieved by regularly supplying external drugs to the body of the patient to thereby reduce the elevated levels of blood glucose.
Historically, diabetes is treated with multiple, daily injections of rapid and long acting insulin via a hypodermic syringe. One or two injections per day of a long acting insulin is administered to provide a basal level of insulin and additional injections of a rapidly acting insulin is administered before or with each meal in an amount proportional to the size of the meal. Insulin therapy can also be administered using an insulin pump that provides periodic or continuous release of the rapidly acting insulin to provide for a basal level of insulin and larger doses of that same insulin at the time of meals. Insulin pumps allow for the delivery of insulin in a manner that bears greater similarity to the naturally occurring physiological processes and can be controlled to follow standard or individually modified protocols to give the patient better glycemic control. In some circumstances, an insulin pump device can store (via input from a clinician or a user) a number of settings (e.g., dosage parameters or other settings) that are customized by the physician for the particular user.
People with diabetes, their caregivers, and their health care providers (HCPs) bear a great deal of cognitive burden in managing intensive medicine therapy. Delivering the correct amount of the medicine at the correct time is an extremely challenging endeavor. Such delivery requires the patient to make dosing determinations multiple times per day and also requires a combination of the patient and the HCP to recalibrate the therapeutic parameters of the therapy on an episodic time frame that varies from individual to individual, and within individuals based on age and/or behavior (e.g., change in exercise, change in diet).
In light of the many deficiencies and problems associated with current systems and methods for maintaining proper glycemic control, enormous resources have been put into finding better solutions. A number of new technologies promise to mitigate some of the cognitive burden that intensive insulin therapy now requires. Developing workable solutions to the problem that are simple, safe, reliable and able to gain regulatory approval has, however, proved to be elusive. For years, researchers have contemplated coupling a continuous glucose monitoring system with an insulin delivery device to provide an “artificial pancreas” to assist people living with diabetes. Their efforts have yet to result in a commercial product. What has been needed is a system and method that provides a level of automatic control of drug delivery devices for improved medicine delivery and glycemic control that is simple, safe, and reliable in a real world setting.